Picking up on the nuances of workplace etiquette can challenge any up-and-coming executive, but for African-Americans with few role models, the learning curve can be even steeper.

Without a mentor in your corner, it's difficult to know whether a situation involves racial insensitivity or youthful naivete, according to Aylwin Lewis, CEO of Chicago-based Potbelly Sandwich Works LLC, who talked last week about some of the challenges he has faced in his career.

In a discussion on "African-American Business Leadership in Chicago," he recalled being passed over — again — for a job. A blunt colleague pointed out, "You have an 8-inch afro."

"I didn't want to cut it," he says, noting the irony of his now-balding head. "My father said, 'So you'll get promoted if you cut your hair? What's the problem?' "

"Cutting my hair was the toughest compromise I've had to make," he says.